Inghouse electric



R. N. EHRH'ART.

AIR PUMP. AFFLICATION FILED NOV- 2|| 19]]- 1,326,652. Patented Dec. 30,1919.

INVENT R.

A; 5 ORNEYS.

rnvrran srairns PAT T, OFFICE- RAYMOND N. EIIRHART, 0F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TOWEST- INGHOUSE ELECTRIC & MANUFACTURING CO., A CORPORATION OF PENNSYLVANIA.

AIR-PUMP;

Specification of Letters Patent. Patented Dec; 30, 1919,

AppIication filed November 21, 1917. Serial No. 203,260.

To all whom it may concern:

Be it known that l, Harmon) N. Erm- HART, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Air-Pumps, of which the following is a specification.

This invention relates to pumps and has for an Object to produce a new and improved pump for handling air, gases and vapors.

A further object is to produce a new and improved air pump of the hydraulic type in which the shock losses are reduced to a minimum.

A further object is to produce a hydraulic airpump in which the air or gas to be pumped is accelerated before it is entrained by the pistons or slugs of water, or other entraining liquid, so that the shock losses are thereby reduced.

A further object is to produce a new and improved hydraulic air pump of high volumetric capacity and in which the volumetric efiiciency is not materially affected by variations in the density of the air or fluids pumped.

These and other objects are attained by means of a pump embodying the features herein described and illustrated in the drawing accompanying and forming a part hereof.

In the drawings: Figure 1 is a diagrammatic sectional view of a well known form of hydraulic air pump.

Fig. 2 is a diagrammatic sectional view of a hydraulic air pump embodying my invention.

The pump diagrammatically illustrated in Fig. 1 is the Leblanc air pump, which is ordinarily employed for exhausting air from condensers. The air withdrawn from the condenser enters an inlet chamber 5, is entrained by Water pistons 6 and is compressed in a diffuser 7 in a manner well known to those skilled in the art. An annular impeller wheel 8 receives water from an internal inlet chamber 9 and is adapted to discharge it tangentially, and into the diffuser 7 in the form of rapidly moving slugs or pistons 6. The momentum of the water is sufficient to carry it and the entrained air through the diffuser 7 and to thereby compress the air and to discharge it against the terminal pressure at the outlet of the diffuser, which is ordinarily atmospheric pressure; I i

It has been found that when the density of theair is high, its inertia is so great that the water pistons 6 are more or less partiallybroken up inaccelerating the air, tliereby lowering the volumetric capacity of the pump. If the density of the air is low, its inertia is so slight that the water pistons are capable of accelerating it without being. broken up and with little shock loss. Consequently the volui'netricefliciency or capacity of the pump illustrated increases as the density of the gas or vapor to be pumped decreases. p y

The air pump illustrated in Fig. 2 is of the same type as the pumpillustrated in Fig. 1, but is constructed soas toincorporate the features of myinvention, and therefore to have ahighfvolumetric efficiency or capacity irrespectiveof the density of the fluids to be pumped. These fluids will hereinafter be referred to as air.

As illustrated, the pump includes an im peller wheel 10, which is provided with laterally projecting bladeslO adaptedto receive water from a distributing nozzle 12 and to deliver the water in the form of separate leaves or pistons into or through a convergent divergent diffuser tube 14. The impeller wheel is located in what may be termed a volute casing 11, which is so arranged with relation to the diffuser 1 1 that the casing is in open and free communication with the diffuser. The water distributing nozzle distributes water from a conduit or passage which terminates in a chamber 12 surrounded by the blades 10 of the impeller 10. The inlet port 11, through which air to be ejected enters the casing 11, is so located that substantially all of the air entering the casing must pass through the blades 10 in leaving the casing. This is accomplished by locating the port 11 so that it directly communicates with what may be termed an air inlet chamber 13, which is surrounded by the row of blades 10*. The blades 10 in effect divide the interior of the casing into the chamber 13 and a volute passage which partially.v surrounds the blades and which terminates in the diffuser 14. The only path of communication between the inlet chamber 18 and the volute passage is through the blades 10 and consequently all of the air entering the chamber 13 must be subjected to the impelling action of the blades in its passage to the diffuser 14.

In operation the air to be compressed is delivered to the inlet chamber 13 and passes in a substantially radial plane through the blades 10 into the volute passage. The water delivered 'to the wheel 10 through the nozzle 12 is broken up by the blades 10 into separate leaves or pistons 17, which are thrown tangentially out of the wheel at high velocity and into the diffuser 14. The air in passing through the blades 10 is also accelerated to substantially the same velocity as the velocity of the water pistons 17, consequently when the air and water meet in the outlet of the volute passage or the inlet of the diiiuser let, the air is entrained without shock and without detrimentally affecting the formation of the water pistons 17. As a result the volumetric capacity of the pump illustrated is not only high, but remains substantially constant irrespective of the density of the fluids to be pumped.

While I have illustrated and described but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as set forth by the appended claims.

What I claim is:

1. A hydraulic air pump having a rotatable centrifugal impeller, a volute casing inclosing the impeller, means for delivering entraining liquid to the interior of the impeller, and means for separately delivering fluids to be compressed to the interior of the impeller so as to accelerate said fluids to substantially the velocity of the entraining liquid before said fluids are entrained by the liquid.

2. A hydraulic air pump comprising in combination a rotatable, bladed impeller having substantially radially disposed passages between the blades communicating with the interior of the impeller, a casing inclosing the impeller and forming a volute passage between the impeller and the casing substantially surrounding the impeller, a diifuser communicating with the volute passage, and means for supplying entraining liquid and a fluid to be compressed to the interior of the impeller.

3. A hydraulic airpump comprising in combination a rotatable, bladed impeller having substantially radially disposed passages between the blades communicating with the interior of the impeller, a casing inclosing the impeller and forming a fluid passage between the impeller and the casing substantially surrounding the impeller and adapted to receive fluid discharged from substantially all of the passages in the impeller, a diffuser communicating with the said fluid passage, and means for supplying entraining liquid and a fluid to be compressed to the interior of the impeller.

In testimony whereof I have hereunto subscribed my name this 19th day of November, 1917.

RAYMOND N. EHRHART.

Witness C. W. MCGHEE. 

